Easy opening container wall

ABSTRACT

An easy opening container wall is provided including a score line defining a panel which is at least partially removable from the wall and a tab with a nose end overlying the container wall and affixed to the removable panel near its starting end and a handle end toward the opposite edge of the container wall, and which further includes a tear strip defined by a U-shaped score with its open end toward the starting end of the removable panel and its starting end attached to the tab.

United States Patent [1 1 Heffner Oct. 9, 1973 EASY OPENING CONTAINERWALL [75] Inventor: Robert E. Heffner, Lower Burrell, Hall H V H l VAttorney-David W. Brownlee [73 Assignee: Aluminum Company of America, 1New Kensington, Pa. [57] ABSTRACT [22] Filed, Dec 27 1971 An easyopening container wall is provided including a score line defining apanel which is at least partially [21] Appl. No.: 212,232 removable fromthe wall and a tab with a nose end overlying the container wall andaffixed to the remov- 2 U. able panel near its Starting end and a handleend E 5' 4 ward the opposite edge of the container wall, and [58] Fieid48 27 44 which further includes a tear strip defined by a U- shapedscore with its open end toward the starting end [56] References Cited ofthe removable panel and its starting end attached to th t b. UNITEDSTATES PATENTS e a 3,604,589 9/1971 Fraze 220/54 9 Claims, 7 DrawingFigures 3,450,300 6/1969 Saunders... 220/54 3,618,815 11/1971Heffner..... 220/48 3,404,801 10/1968 Silver 220/54 Patented Get. 9,1973 2 SheetsSheet 1 FIG. 3.

FIG. I,

FIG. 7.

Patented Oct. 9, 1.973 3,764,038

2 Sheets-Sheet.

FIG. 6.

EASY OPENING CONTAINER WALL BACKGROUND OF THE INVENTION It is known toprovide easy Opening container walls with pull tabs which are attachedthereto at two locations as disclosed in US. Pat. Nos. 3,618,8l;

3,604,589; 3,477,608 and 3,221,924, among others. In

the container walls disclosed in these patents, one of the attachmentsis made to a relatively small tear section which is completely severedfrom the container wall prior to removal of a large panel portion. Suchtear sections are usually provided for venting gases or air into or outof a container on which the wall is affixed. There are also a number ofdisclosures of easy opening container walls which include a primaryscore around a removable panel portion and a secondary score within theremovable panel portion to facilitate rupture of the primary score. Suchdisclosures are contained in US. Pat. Nos. 3,450,300 and 3,404,801,among others.

SUMMARY OF THE INVENTION This invention provides an easy openingcontainer wall with a pull tab thereon which includes means attached tothe handle and of the tab and to the container wall for controllingbending of a removable panel in the container wall during opening toinsure initial opening of a relatively large portion of the removablepanel with a minimum of effort. In a preferred embodiment of theinvention, such bend control means comprises a U- shaped tear strip in acontainer wall with the open end of the tear strip toward an adjacentedge of the removable panel and the closed end of the tear stripattached to the handle end of a tab.

Accordingly, an object of the invention is to provide an easy openingdevice which includes means for controlling bending of a removable panelportion during opening.

Another object of the invention is to provide an improved easy openingcontainer wall with means therein for facilitatingseverance of aremovable panel from the wall.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects andadvantages of the invention will be more fully understood andappreciated with reference to the following description and the drawingsappended hereto wherein:

FIG. 1 is a top plan view of a container wall of the invention prior toattachment of a tab to the end;

FIG. 2 is a bottom plan view' of a tab for attachment to the containerwall of FIG. 1;

FIG. 3 is a top plan view of the container wall of FIG. 1 afterattachment of the pull tab of FIG. 2 to the end;

FIG. 4 is a cross-sectional view of a container wall of the inventionillustrating initiation of opening;

FIG. 5 is a cross-sectional view similar to FIG. 4 and furtherillustrating initiation of rupture of the score line around the startingend of the removable panel in the container wall;

FIG. 6 is a cross-sectional view similar to FIGS. 4 and 5 and furtherillustrating completion of the lifting portion of the opening sequence;and

FIG. 7 is a perspective view of a container wall of the inventionillustrating further rupture of the primary score around the removablepanel.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. I, a sheet metalcontainer and wall 10 for a can or other container is illustrated beforea tab is attached to the end. Preferably, can end 10 is made of aluminumor an alloy thereof, although it can also be made of other metals or ofplastic. Wall 10 may have peripheral seam 14 therearound for joining itto a container body by conventional methods, and may have a peripheralgroove 16 adjacent seam 14 to strengthen the end against reversal oroutward doming. A circular line of weakness or score 18 is cut in wall10 inwardly of and adjacent to groove 16 to define a removable panel 20for providing acess to the contents of a container on which the wall isseamed. Ends of this type with a score line which permits removal of amajor portion of the end wall are generally called full panel pull-out"or full panel removal" type ends. In order to facilitate gripping a tabwhich will be affixed to wall 10, a depression or finger well 22 may beembossed or otherwise formed in the wall as is conventional. A gapbetween the end of a tab and container wall 10 in finger well 22 permitsa user to insert a finger or finger nail under the end of the tab tolift it.

It is a feature of this invention that container wall 10 includes asecond line of weakness or score 26 defining a tear strip 28 which isonly partially severable from the container end, and which is attachedto a tab to control bending of removable panel 20 as will be described.Some previously known easy opening container walls have included asecond score line for facilitating rupture of the primary score, andsome previously known easy opening container walls have included twoattachments of a tab to the removable panel, but none has included asecondary score in the removable panel defining a partially severablestrip which is attached to the tab to control bending of the panel. Byproviding a tear strip which is only partially severable from removablepanel 20, the present invention provides a permanent connection betweenthe removable panel in container wall 10 and the handle end of a tabwhich controls bending of opening the opening panel along apredetermined line. The location of such a predetermined bend line isgenerally dependenton the location of the connection of tear strip 28 tocontainer wall 10. This connection of the tear strip 28 to the containerwall 10 is defined by the open end of U-shaped score 26. By locating theopen end of U-shaped score 26 a substantial distance, approximately 1%inch in container wall 10 selected for illustration, from the score linearound the starting end of removable panel 10, a relatively large arc ofthe removable panel will be opened during initial lifting of the tab.This portion of the removable panel is plunged into a container on whichend wall 10 is seamed and helps to reinforce the end against doming orbuckling which can make it difficult to further rupture the primaryscore.

Closure 10 may further include score lines 27 extending outwardly fromthe open end of U-shaped score 26 along a chordal line through such openend and reversely curved wing-shaped score segments extending from theouter ends of score lines 27 around removable panel 20 adjacent andparallel to score 18. Score lines 27 provide weakening in removablepanel 10 to facilitate removal of the panel as will be described. Scoresegments 29 may extend approximately one-half of the way around end wall10, although the invention is not limited with respect to the length ofsuch segments. The location of score lines 27 and the length of tearstrip 28 are not considered to be critical to the invention. In end wallselected for illustration, tear strip 28 extends from score lines 27which are located approximately one-eighth of the way across removablepanel, to approximately the center of the panel, and is exemplary of anend wall of the invention.

End wall 10 further includes two integral upstanding hollow rivets 30and 32, one in the starting end of removable panel and one in thestarting end of tear strip 28 for attachment of a tab to the wall atthese two locations. Rivets 30 and 32 are preferably located on adiametrical line across end wall 10 through the longitudinal axis oftear strip 28. Rivets 30 and 32 may be integrally formed from a sheetmetal end wall as is well known in the container and closure art.

Turning to FIG. 2, a tab 40 is illustrated for attachment to a can end10. Tab 40 may be formed from sheet metal, preferably aluminum or analloy thereof, and has a triangular shaped nose end 42 and a handle end44 with a large aperture therein to facilitate gripping by a user.Referring further to FIG. 3 et. seq., tab 40 has a substantially planarupper wall with two downwardly embossed wells 46 and 48 therein and withapertures in the bottom of the wells for receiving integral rivets forattachment of the tab to a container wall. To strengthen tab 40 andavoid sharp edges, the sheet metal of the tab may be curled downwardlyand inwardly around the large finger aperture in the handle end of thetab and along the outer edges of the tab to form beads 50 and 52respectively. Nose end 42 of tab 40 may also be reinforced by means ofthe downwardly directed flange 54 which may have a point 56 on the endof the tab nose to facilitate rupture of the score line at the startingend of a removable panel in a can end.

FIG. 3 illustrates a tab 40 attached to a container end 10 by means ofintegral rivets 30 and 32. As attached, nose end 42 of tab 40 overliesthe opening end of panel 20, and handle end 44' of the tab overlies tearstrip 28 toward the opposite side of the container end. The outer end ofhandle end 44 is disposed over finger well 38 in container end 10 sothat a user can more easily grip the handle end of the tab.

FIGS. 4-7 illustrate opening of a container on which end wall 10 isseamed by lifting tab 40 and pulling it to rupture score lines 18 and 26in the wall. It is seen in FIG. 4 that initial lifting of handle end 44of tab 40 exerts an upward force on rivet 32 to rupture score line 26around tear strip 28 to partially sever the tear strip from the end.This forms a vent in container wall 10 to permit pressurized gases toescape from the can, or air to enter the can, and also facilitatesfurther lifting of tab 40 to initiate rupture of score 18 as will bedescribed. Since the vent is located under tab 40, the vent opening isshielded by the tab and accidental spraying of the contents of the canon the user during opening is substantially prevented.

Rupture of score line 26 around tear strip 28 permits a substantiallength of tab 40 to be raised slightly above the surface of end wall 10as illustrated in FIG. 4, and facilitates application of force againstthe starting end of removable panel 20 by the nose of the tab. Thisforce initiates rupture of score line 18 as illustrated in FIG. 5.Lifting of tab 40 may also be facilitated by upward doming or flexing ofend wall 10 as illustrated. If tab 40 could not be lifted off thesurface of end wall it to facilitate gripping its handle end, initiationof rupture of score 18 could be difficult. In some prior end wallstructures such as those illustrated in US. Pat. No. 3,618,815, therivet connection between the tab and the removable panel is located asubstantial distance from the starting end of the removable panel inorder to open a relatively large area in the end wall, and this makes itdifficult to lift the tab to initiate rupture of the score line aroundthe removable panel. In others, the connection is located relativelyclose to the score line around the removable panel, but these endsinclude no means for initially plunging a relatively large portion ofthe panel into a container as is desired for some purposes. The presentinvention provides an end wall with a tab thereon which can be initiallylifted to facilitate gripping to rupture the score line around thestarting end of a removable panel and also plunges a relatively largeportion of the removable panel into a can as will be described.

As illustrated in FIG. 4, end wall 10 of the invention is unique in thattear strip 28 in removable panel 20 remains attached to container wall10 as the removable panel is plunged into a can. Tear strip 28 therebyprovides a connection between handle end 44 of the tab 40 and containerend 10 and forces bending of the opening flap to occur along apredetermined line. Tab 40 is substantially rigid and is attached toboth tear strip 28 and removable panel 20 so that the connection of thetear strip to the container wall controls pivoting of the tab after thetear strip has been partially severed from the end wall. Continuedlifting of tab 40 therefore hinges about the chordal line on which scorelines 27 are located to plunge a relatively large flap of panel 20 intocontainer 62 as illustrated in FIG. 6. It is believed that initiallyopening a relatively large are or flap such as this upon lifting of tab40 facilitates removal of panel 20 because it prevents doming orbuckling of the panel when tab 40 is pulled upward to rupture score 18around a periphery of the removable panel. If only a short arc of score18 were ruptured when tab 40 is lifted to a vertical position, the flapof metal from panel 20 which is turned downwardly into a container isnot of sufficient strength to prevent doming or buckling of the panelwhen the tab is pulled outwardly to sever the remaining length of thescore. When a panel domes during such removal, the score around theperiphery of the panel is placed in tension rather than in shear, and itis much more difficult to rupture the score in tension thanin shear.Accordingly, buckling or doming of the removable panel can make itdifficult to effect rupture of the score around the panel and removal ofthe panel. End wall 10 solves this problem by rupturing a relativelylong are of score 18 and bending a relatively large flap of metal into acan to prevent any doming when the tab is pulled to effect completeremoval of the panel.

It is another feature of end wall 10 that score segments 29 extendaround approximately one-half of panel 20 to facilitate rupture of score18 during removal of the panel. When tab 40 is pulled upwardly asillustrated in FIG. 7, score 26 ruptures along its entire length,including lines 27 and segments 29, as score 18 is being ruptured. Thisresults in the application of the removal force closely adjacent score18 to ensure that the residual metal in such score is placed in shearrather than in tension. The pulling force which is applied to tab 40 istransmitted to removal panel 20 through the strips of metal betweenscores 29 and 18 on either side of the removal panel. Since these stripsof metal are contiguous score 18, the force which is applied throughsuch strips will also be applied contiguous score 18 rather than beingapplied more centrally in the removable panel. The ends of score 29could extend further around removable panel 20, but it is believed thatapproximately half way is an optimum length. Beyond that point, score 18is again coverging and there is less tendency of removal panel 20 todome. lf scores 29 were terminated short of the half way point, domingof the removable panel 20 could be excessive and result in difficulty inrupturing score 18.

It is therefore seen that an easy opening container wall is provided inwhich initiation of rupture of the score line is facilitated byincreasing the mechanical advantage of the tab, but in which arelatively large arc of the primary score is ruptured around theremovable panel to reinforce the removable panel against upward domingor buckling during removal of the panel. Although a particularembodiment of the invention has been illustrated and described, it willbe apparent to those skilled in the art that numerous variations can bemade in the details of such embodiments without departing from theinvention.

What is claimed is:

1. An easy opening container wall having a substantially circular lineof weakening therein defining a removable panel having a starting endadjacent the periphery of the wall and a partially removable tear stripin said removable panel with a starting end toward the center of thecontainer wall and a terminal unscored end toward the starting end ofsaid removable panel, said container wall further having a tab attachedto said removable panel and to said tear strip in their starting endswhereby said tear strip remains attached to said tab and said removablepanel during opening to control bending of said removable panel.

2. An easy opening device as set forth in claim 1 in which said tab ismade of sheet metal and has reinforced portions along its longitudinaledges to make it substantially rigid.

3. An easy opening device as set forth in claim 2 in which said tab hasdownwardly curled edge portions.

4. An easy opening device as set forth in claim 3 in which said tab hasdownwardly formed wells therein and apertures in the bottoms of thewells through which the tab is attached to the container wall.

5. An easy opening container wall as set forth in claim 1 in which saidtear strip is defined by a Ushaped score.

6. An easy opening container wall as set forth in claim 5 in which saidU-shaped score has outwardly extending segments on its open end. locatedon a chordal line in said removable panel.

7. An easy opening container wall as set forth in claim 5 in which saidU-shaped score has curved segments on its open end extending paralleland adjacent to said circular score along portions thereof on eitherside of the starting end of the removable panel.

8. An easy opening container wall as set forth in claim 1 in which adepressed well is provided in thewall under the handle end of the tab.

9. In an easy opening device in a container wall comprising a circularline of weakness in the container wall defining a panel which is atleast partially removable from the container wall and having a startingend adjacent the periphery of the container wall and a tab attached tothe starting end of the panel, the improvement comprising a second lineof weakness in the container wall within said removable panel defining atear strip having a starting end toward the center of the container walland a terminal unscored end toward the starting end of said removablepanel, and said tab is attached to said tear strip near its startingend, whereby said tear strip remains attached to the container wallduring opening to control bending of said removable panel.

1. An easy opening container wall having a substantially circular lineof weakening therein defining a removable panel having a starting endadjacent the periphery of the wall and a partially removable tear stripin said removable panel with a starting end toward the center of thecontainer wall and a terminal unscored end toward the starting end ofsaid removable panel, said container wall further having a tab attachedto said removable panel and to said tear strip in their starting endswhereby said tear strip remains attached to said tab and said removablepanel during opening to control bending of said removable panel.
 2. Aneasy opening device as set forth in claim 1 in which said tab is made ofsheet metal and has reinforced portions along its longitudinal edges tomake it substantially rigid.
 3. An easy opening device as set forth inclaim 2 in which said tab has downwardly curled edge portions.
 4. Aneasy opening device as set forth in claim 3 in which said tab hasdownwardly formed wells therein and apertures in the bottoms of thewells through which the tab is attached to the container wall.
 5. Aneasy opening container wall as set forth in claim 1 in which said tearstrip is defined by a U-shaped score.
 6. An easy opening container wallas set forth in claim 5 in which said U-shaped score has outwardlyextending segments on its open end located on a chordal line in saidremovable panel.
 7. An easy opening container wall as set forth in claim5 in which said U-shaped score has curved segments on its open endextending parallel and adjacent to said circular score along portionsthereof on either side of the starting end of the removable panel.
 8. Aneasy opening container wall as set forth in claim 1 in which a depressedwell is provided in the wall under the handle end of the tab.
 9. In aneasy opening device in a container wall comprising a circular line ofweakness in the container wall defining a panel which is at leastpartially removable from the container wall and having a starting endadjacent the periphery of the container wall and a tab attached to thestarting end of the panel, the improvement comprising a second line ofweakness in the container wall within said removable panel defining atear strip having a starting end toward the center of the container walland a terminal unscored end toward the starting end of said removablepanel, and said tab is attached to said tear strip near its startingend, whereby said tear strip remains attached to the container wallduring opening to control bending of said removable panel.